.concept-page { max-width: 1120px; padding-inline: 40px; }
.concept-header { max-width: 780px; margin: 32px 0 36px; }
.concept-eyebrow { margin-bottom: 14px; color: var(--physics); font-size: 11px; letter-spacing: .08em; }
.concept-page .concept-header h1 { font-size: clamp(29px, 4vw, 44px); line-height: 1.3; }
.concept-header .info-lead { margin-top: 20px; color: var(--text-sub); font-size: 17px; line-height: 1.9; word-break: keep-all; overflow-wrap: anywhere; }
.concept-start { display: inline-block; margin-top: 22px; font-size: 13px; }
.concept-hero { max-width: 780px; margin: 0 0 40px; }
.concept-hero > img { display: block; width: 100%; height: auto; aspect-ratio: 19 / 11; object-fit: contain; border: 1px solid var(--line); border-radius: 9px; background: #111216; }
.concept-hero figcaption { padding-top: 10px; font-size: 12px; color: var(--text-mute); }
.concept-card-preview { display: block; margin: -20px -20px 18px; overflow: hidden; border-bottom: 1px solid var(--line); border-radius: 8px 8px 0 0; background: #111216; }
.concept-card-preview img { display: block; width: 100%; height: auto; aspect-ratio: 19 / 11; object-fit: contain; }
.concept-layout { display: grid; grid-template-columns: minmax(0, 1fr) 190px; column-gap: 48px; align-items: start; }
.concept-toc { grid-column: 2; grid-row: 1; position: sticky; top: 32px; padding-left: 20px; border-left: 1px solid var(--line); }
.concept-page .concept-toc h2 { font-size: 12px; margin: 0 0 14px; color: var(--text-mute); }
.info-page.concept-page .concept-toc a { display: block; margin-top: 12px; font-size: 12px; line-height: 1.7; color: var(--text-sub); text-decoration: none; word-break: keep-all; overflow-wrap: anywhere; }
.info-page.concept-page .concept-toc a:hover { color: var(--physics); text-decoration: underline; }
.concept-article { grid-column: 1; grid-row: 1; min-width: 0; }
.concept-page .concept-article section { margin: 0 0 42px; scroll-margin-top: 24px; }
.concept-page .concept-article h2 { font-size: 21px; line-height: 1.6; word-break: keep-all; overflow-wrap: anywhere; }
.concept-page .concept-article p, .concept-page .concept-article li { line-height: 2; word-break: keep-all; overflow-wrap: anywhere; }
.concept-formula { margin: 18px 0; padding: 20px; background: var(--surface); border: 1px solid var(--line); border-radius: 8px; }
.concept-formula p { font-family: Georgia, 'Pretendard Variable', serif; font-size: 17px; color: var(--text); }
.concept-page table { margin-top: 18px; }
.concept-page caption { text-align: left; font-size: 12px; padding-bottom: 10px; color: var(--text-mute); }
.concept-page th, .concept-page td { min-width: 0; }
.concept-example { padding: 20px 22px; background: var(--physics-soft); border-left: 3px solid var(--physics); border-radius: 0 8px 8px 0; }
.concept-page .concept-example h3 { margin: 0 0 12px; font-size: 15px; line-height: 1.8; }
.concept-experiments, .concept-cards { display: grid; gap: 12px; }
.info-page.concept-page :is(.concept-experiments, .concept-cards) > a { display: block; padding: 20px; background: var(--surface); border: 1px solid var(--line); border-radius: 8px; text-decoration: none; }
.concept-page :is(.concept-experiments, .concept-cards) > a:hover { border-color: var(--physics); }
.concept-page .concept-experiments > a > span { font-size: 15px; }
.concept-page .concept-experiments p, .concept-page .concept-cards p { margin-top: 8px; color: var(--text-sub); font-size: 13px; line-height: 1.9; }
.concept-page .concept-cards h3 { margin: 0; font-size: 16px; }
.concept-cards > a > span:not(.concept-card-preview) { display: block; margin-top: 14px; font-size: 12px; }
.concept-page .concept-related { display: flex; flex-wrap: wrap; gap: 10px 22px; padding: 0; list-style: none; }
.concept-page .concept-related li { margin: 0; }
.concept-bottom { display: flex; flex-wrap: wrap; gap: 16px 28px; padding-top: 24px; border-top: 1px solid var(--line); font-size: 13px; }
.concept-index-inner { max-width: 850px; margin-inline: auto; }
.concept-index-inner .concept-cards { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.concept-page a:focus-visible { outline: 2px solid var(--physics); outline-offset: 5px; }
@media (max-width: 1100px) {
  .concept-layout { display: flex; flex-direction: column; gap: 32px; }
  .concept-toc { position: static; width: 100%; padding: 20px; background: var(--surface); border: 1px solid var(--line); border-radius: 8px; }
  .concept-page .concept-toc a { margin-top: 9px; }
  .concept-article { width: 100%; }
}
@media (max-width: 600px) {
  .concept-page { padding-inline: 20px; }
  .concept-header { margin-top: 24px; }
  .concept-header .info-lead { font-size: 15px; }
  .concept-index-inner .concept-cards { grid-template-columns: 1fr; }
  .concept-formula, .concept-example { padding: 16px; }
  .concept-page th, .concept-page td { padding: 10px; font-size: 12px; overflow-wrap: anywhere; }
}